The national standard for industrial 235 steel pipes GB/T81622018

GB/T81622018 is a Chinese national standard that specifies the technical requirements, inspection rules, marking, packaging, and quality certificates for seamless steel pipes used for structural and mechanical purposes. The 235 refers to the minimum yield strength of the steel pipe is 235MPa.

First, the material and classification of steel pipes

Seamless steel pipe materials specified in GB/T81622018 include: 10, 20, 35, 45, Q345, Q390, 10CrMo910, 12CrMo, 12CrMoV, 12Cr1MoV, 15CrMo, 35CrMo, 40Cr, 42CrMo, etc.

According to different uses, seamless steel pipes can be divided into structural steel pipes, hydraulic prop steel pipes, oil casing steel pipes, automobile axle casings, high-pressure oil pipes, low-pressure boiler pipes, hydraulic pipes, etc.

Second, technical requirements

1. Appearance quality: The surface of the steel pipe must not have defects such as cracks, creases, rips, oxide scale, and oil stains.

2. Dimensional deviation: The outer diameter, wall thickness and length of the steel pipe should meet the standard requirements and have allowable deviations.

3. Mechanical properties: Steel pipes should undergo tensile tests and flattening tests, and their mechanical properties should meet standard requirements.

4. Chemical composition: The chemical composition of steel pipes should comply with standard requirements, among which the contents of C, Si, Mn, P, S, Cr, Ni, Cu, and other elements are clearly defined.

5. Hardness: The hardness of the steel pipe should meet the standard requirements.

Third, marking and packaging

The marking of steel pipes should specify the steel number, size, length, production batch number, standard number, marking, and other information about the steel pipe. The packaging of steel pipes should meet standard requirements and have corresponding quality certificates.

Fourth, application scope

Seamless steel pipes specified in GB/T81622018 are widely used in petroleum, chemical industry, electric power, metallurgy, machinery, aviation, aerospace, and other fields. Among them, steel pipes such as high-pressure oil pipes, low-pressure boiler pipes, and hydraulic pipes are widely used in industrial production.

In short, the introduction of the GB/T81622018 standard has played an important role in standardizing the production and application of seamless steel pipes. As a consumer, when purchasing steel pipes, you should pay attention to check that they meet standard requirements to ensure the quality and safety of the product. At the same time, steel pipe manufacturers must also produce in strict accordance with the standard requirements to ensure that the quality of the products meets the standard requirements.